JP4304769B2 - Concentration control method for water treatment chemicals in cooling water system - Google Patents

Description

【００３８】
〔式において、Ｒ^１、Ｒ^２は、独立して水素、ハロゲン又は炭素数１〜４を有するアルキル基であるか、或いは、一緒になって飽和、不飽和もしくは芳香族の５又は６員環を形成するものであり、Ｙは、水素、炭素数１〜１８を有する非置換又はハロゲン置換アルキル基、炭素数２〜８を有する非置換又はハロゲン置換アルケニル基、炭素数２〜８を有する非置換又はハロゲン置換アルキニル基、炭素数３〜８を有する非置換又はハロゲン置換シクロアルキル基、炭素数１０までの非置換、ハロゲン置換、アルキル（アルキル基の炭素数は１〜４である）置換又はアルコキシ（アルコキシ基の炭素数は１〜４である）置換アラルキル基、炭素数１０までの非置換、ハロゲン置換、アルキル（アルキル基の炭素数は１〜４である）置換又はアルコキシ（アルコキシ基の炭素数は１〜４である）置換アリール基より選ばれる基である。〕
【００３９】
置換基Ｙの若干の具体例としては、メチル、エチル、プロピル、ブチル、へキシル、オクチル、シクロへキシル、４−メトキシフェニル、４−クロロフェニル、３，４−ジクロロフェニル、ベンジル、４−メトキシベンジル、４−クロロベンジル、フェネチル、４−フェニルブチル、クロロメチル、クロロプロピル、水素等が挙げられる。
【００４０】
また、本発明で検出対象薬品となり得るイソチアゾロン類の若干の具体例としては、２−メチル−３−イソチアゾロン、５−クロロ−２−メチル−３−イソチアゾロン、４，５−ジクロロ−２−ｎ−オクチル−３−イソチアゾロン等が挙げられる。これらのイソチアゾロン類は、単独で使用しても良いし、二種類以上を混合して使用しても良い。
【００４１】
本発明の方法において予め酸化されたポリカルボン酸類（または、未酸化のポリカルボン酸類＋イソチアゾロン類）を検出する際の測定条件（化学発光反応条件）としては、特に制限はなく、測定温度、ｐＨ、試料水の濃度等は任意に設定することができる。ただし、このような検出対象物質の検出感度は、測定温度、ｐＨの影響を受けるため、これらに関しては一定した測定条件で測定を行うのが望ましい。
【００４２】
冷却水系への添加対象である水処理用薬品としては、例えば、ポリカルボン酸類を始めとする水溶性ポリマー等の分散剤（防食剤や凝集剤等としても機能するものあり）、ホスホン酸類、燐酸塩、珪酸塩、亜硝酸塩、タングステン酸塩、硼酸、亜鉛塩、芳香族カルボン酸塩、亜硫酸塩、ヒドラジン、タンニン、リグニン、リグニンスルホン酸塩、アスコルビン酸ナトリウム、エルソルビン酸ナトリウム、グルコース等の防食剤、ベンゾトリアゾール、トリルトリアゾール、メルカプトベンゾチアゾール等のアゾール系銅防食剤、アンモニウム系化合物、アミン系化合物、塩素系化合物、臭素系化合物、イソチアゾロン類を始めとする有機窒素硫黄系化合物等の殺菌・殺藻剤を挙げることができる。本発明方法において検出対象薬品となり得るポリカルボン酸類と、イソチアゾロン類を始めとする他の水処理用薬品とを併用したり、配合して使用することは何ら差し支えなく、冷却水系の循環水中のポリカルボン酸類の濃度を監視することによりこれらの水処理用薬品の添加補充量を制御して冷却水系の水処理用薬品の濃度管理を行うこともできる。
【００４３】
【発明の実施の形態】
以下、本発明の好ましい実施の形態を説明するが、本発明はこのような実施の形態に限定されるものではない。
【００４４】
本発明の冷却水系の水処理用薬品の濃度管理方法において、ポリカルボン酸類の検量線を予め作成しておく。この様な検量線は、ポリカルボン酸類を含まないブランク水及び異なる既知ポリカルボン酸類濃度の幾つかの対照水の化学発光強度の測定を行って作成する。これらのブランク水や対照水も、循環水の試料を予め酸化する際と同じ酸化反応条件で予め酸化して化学発光強度の測定を行う。なお、ブランク水としては、ポリカルボン酸類のみを含まず他の成分（例えば、不純物成分や他の水処理用薬品）は同じブランク水を用いるのが測定精度の点では好ましいことは勿論である。
【００４５】
検出対象薬品であるポリカルボン酸類は、通常の循環水そのままを用いて化学発光法により充分な感度で検出できるが、必要に応じて希釈、濃縮、または、精製等の操作を行ってから化学発光法による検出に供してもよい。例えば、循環水がポリカルボン酸類とイソチアゾロン類の両方を含む場合にこれらを別々に検出するための精製操作の一例としては、循環水の試料に対して、必要に応じて試料のｐＨ調整（例えば、ｐＨ２〜３へ調整）、吸着剤ゲルへのポリカルボン酸類の選択的吸着、溶離等の処理操作を行い、得られるポリカルボン酸類含有溶出液（精製液）を予め酸化して、化学発光法によりその増幅された化学発光強度を測定し、その測定値を最初の冷却水系のポリカルボン酸類濃度に換算し、その定量を行うこともできる（米国特許第４５１４５０４号参照）。この場合、分析精度や分析安定性を高めると共に、冷却水系の循環水中のポリカルボン酸類濃度が特に低い時には上記処理操作を通じてポリカルボン酸類の濃縮を行うことができる。一方、上記処理操作で得られるイソチアゾロン類含有溶出液（精製液）は予め酸化することなく化学発光法によりその化学発光強度を測定し、その測定値を最初の冷却水系のイソチアゾロン類濃度に換算し、精度良くその定量を行うこともできる。ただし、この操作は煩雑で、時間と労力を要する。しかし、この方法を実施する場合も本発明の実施であることに変わりない。
【００４６】
次に、本発明において好ましい化学発光法を実施する装置の一例について説明する。装置は、基本的にキャリア液を送液するポンプ、ポリカルボン酸類（または、更にイソチアゾロン類）を含む循環水の試料をキャリア液中に注入するインジェクター、ルテニウム錯体及び／又はセリウムの硝酸アンモニウム塩等の検出用試薬を含む溶液を送液するポンプ、試料を予め酸化する試料酸化反応器、ルテニウム錯体及び／又はセリウムの硝酸アンモニウム塩等の検出用試薬を酸化する試薬酸化反応器、キャリア液と試料との酸化された混合水及び酸化されたルテニウム錯体及び／又は酸化されたセリウムの硝酸アンモニウム塩等の検出用試薬の溶液を混合する混合機、化学発光を検出する検出器、検出器で得られたデータを記録するデータプロセッサーで構成される。ただし、場合によっては、循環水の試料を予め酸化してキャリア液中に注入してもよく、また、循環水の試料そのものを連続的に供給し、キャリア液を用いないこともあるため、後者の系ではインジェクターは不要となる。また、混合機としては、インラインミキサー、混合コイル等でもよく、混合後の混合物は直ちに検出に供されるのが望まれるので、検出器に混合機を付設したり、検出器中で攪拌混合や合流混合するような構成の検出器が混合機を兼ねるものでも良い。また、データプロセッサーは、上記検出器から出力される化学発光強度を電気信号として取込み、そのデータを記録し、必要に応じて該データをポリカルボン酸類濃度に換算して記録、表示する構成であるのが好ましい。このようなデータプロセッサーは、化学発光強度対ポリカルボン酸類濃度の検量線を内包し、ポリカルボン酸類濃度計算等の演算処理を行うことができるのが好ましく、更に必要に応じて試薬供給ポンプを起動、停止させるための出力信号も発することができるのが好ましい。
【００４７】
上記の試薬酸化反応器としては、ルテニウム錯体及び／又はセリウムの硝酸アンモニウム塩等の検出用試薬を酸化させる酸化方式により異なる反応器が用いられる。例えば、酸化剤として二酸化鉛、酸化ビスマス、酸化金などの金属酸化物を用いる場合には、この金属酸化物をカラムに充填させたものを反応器として用いる。また、酸化剤としてペルオキソ二硫酸カリウムや半導体光触媒を担体上に固定化した固体酸化剤等を用いる場合には、かかる酸化剤とルテニウム錯体及び／又はセリウムの硝酸アンモニウム塩等の検出用試薬を共存させた状態で紫外線等の光を照射して光化学的に酸化させることが可能な装置を反応器として用いる。この場合、光源としては、紫外線ランプやブラックライトの他にも一般的な蛍光灯や太陽光線などを用いることができる。一方、電極上で電気化学的にルテニウム錯体及び／又はセリウムの硝酸アンモニウム塩等の検出用試薬を酸化する方法を採用する場合には、安定化直流電源を備えた電解酸化装置を反応器として用いる。ただし、検出用試薬として硝酸二アンモニウムセリウム（IV）を用いる場合には試薬酸化反応器は不要である。また、試薬酸化反応器は、酸化された試薬が不安定なため、基本的には極めて短時間に試薬の供給と排出を行え且つその中では連続的に酸化を進行させる酸化反応器となる。
【００４８】
一方、試料酸化反応器は、好ましくは固体酸化剤を用いて循環水の試料を酸化する試料酸化装置である。用い得る固体酸化剤としては、二酸化鉛、酸化ビスマス、酸化金等の金属酸化物や半導体光触媒を担体上に固定化した固体酸化剤が挙げられるが、二酸化鉛、酸化ビスマス、酸化金等の金属酸化物は長期間の使用で消耗してしまうため、これに比べて光照射により触媒が再生する半導体光触媒を担体上に固定化した固体酸化剤が好ましく用いられる。固体酸化剤として半導体光触媒を担体上に固定化した酸化剤を用いる場合、酸化方法としては、この酸化剤と循環水の試料を接触させた状態で紫外線等の光を照射して光化学的に酸化する方法となる。試料酸化反応器の具体例を挙げると、連続的に酸化反応を実施したい場合には、二酸化鉛、酸化ビスマス、酸化金等の金属酸化物をカラムに充填させ、試料をカラムに流す構成の反応器や半導体光触蝶を担体上に固定化した固体酸化剤をカラムに充填させ、試料をカラムに流しながらカラムに光を照射できる反応器を用いることができ、一方、バッチ式で酸化反応を実施したい場合には、二酸化鉛、酸化ビスマス、酸化金等の金属酸化物を容器中で試料と接触させることができる反応器や半導体光触媒を担体上に固定化した固体酸化剤を容器中で試料と接触させ、容器に光を照射できる反応器を用いることができる。
【００４９】
図１は、このような装置の一例を示すフロー図である。キャリア液とルテニウム錯体及び／又はセリウムの硝酸アンモニウム塩を含む溶液（図１では、この溶液を「Ｒｕ錯体溶液」で代表している）は、それぞれポンプ１、２により供給される。なお、試薬用の酸化剤としてペルオキソ二硫酸カリウム等の水溶性酸化剤を用い、光化学的に酸化する場合には、ルテニウム錯体及び／又はセリウムの硝酸アンモニウム塩を含む溶液にこの酸化剤を予め添加しておくことが望ましい。ルテニウム錯体及び／又はセリウムの硝酸アンモニウム塩を含む溶液は、試薬酸化反応器４で連続的に酸化されて混合器６に供給される。一方、キャリア液には、インジェクター３からポリカルボン酸類を含む循環水の試料の一定量が注入され、試料酸化反応器５で連続的に酸化されて混合器６に供給される。混合器６ではキャリア液と試料との酸化された混合水及び酸化されたルテニウム錯体及び／又はセリウムの硝酸アンモニウム塩の溶液が混合されて反応し、化学発光が起こる。この化学発光が混合器６の直後に設置された検出器７で検出され、化学発光強度やポリカルボン酸類濃度変換値がデータプロセッサー８に記録される。データプロセッサー７は、Ａ／Ｄコンバーター、コンピューター、表示装置（ＣＲＴ、液晶ディスプレイ、レコーダー等）を包含するのが一般的である。
【００５０】
以上述べた様に、本発明によるポリカルボン酸類濃度測定手順は、通常、簡便で、測定値も再現性良く迅速に得られるために、現場での水処理用薬品の濃度管理を簡単に行うことができる。つまり、水処理用薬品の濃度の管理は、本発明に従った化学発光法によるポリカルボン酸類濃度の測定値に基づいて不足分の水処理用薬品をバッチ投入するか、水処理用薬品の注入ポンプのストロークを調整し、例えば、クーリングタワーの下部水槽に連続的に注入する。また、オンライン装置として化学発光分析機器（例えば、図１の装置）を設置し、該分析機器からの出力信号を変換部で操作出力に変換し、水処理用薬品注入ポンプを作動させることにより、水処理用薬品の濃度を自動制御することもできる。こうして、水処理用薬品が効果を発揮する下限濃度（限界濃度）以上、好ましくはほぼ最適濃度を循環水中で保持する様にする。水処理薬品の投与の態様は、冷却水系の長期運転停止後の運転開始時に多量の水処理用薬品（特に防食剤）を投与する「基礎投入」と冷却水系の通常運転時に系内での薬品の消耗、飛散や強制ブローによる循環水中の薬品濃度の低下を補う「保持投入」とがあるが、何れの場合も本発明を適用できる。
【００５１】
【実施例】
以下、実施例により、本発明を更に具体的に説明するが、本発明は実施例に限定されるものではない。
【００５２】
図１に示した装置を用いて、本発明に従った化学発光法によるポリカルボン酸類の選択的検出を行った。図１中の試薬酸化反応器４としては、電解酸化装置（コメット社製、商品名「コメット２０００」）を用いた。
【００５３】
また、試料の酸化処理方法は、酸化剤として半導体光触媒を担体上に固定化した固体酸化剤を用い、固体酸化剤と試料を接触させた状態で遠紫外線を照射して光化学的に酸化する方法を用いた。図１中の試料酸化反応器５としては以下の構造のものを用いた。即ち、この固体酸化剤は、半導体光触媒としての酸化チタン（ドイツ・デグサ社製、商品名「Ｐ２５」）を担体としての高密度ポリエチレンペレット（東ソー株式会社製、商品名「ニポロンハード２５００」）と混合し、加熱攪拌して熱融着させて酸化チタン担持ポリエチレン粒状体（酸化チタン担持量：３重量％）の形として調製したもので、この酸化チタン担持ポリエチレン粒状体をテフロンチューブに詰めて、テフロンチューブをブラックライト（波長：３５２ｎｍ）に巻きつけた状態として試料酸化反応器を構成した。この状態で遠紫外線を照射して光化学的に試料を酸化した。なお、酸化反応時間は１０秒であった。
【００５４】
実施例１
ポリカルボン酸類を含む複数の化学発光原因物質が共存するモデル試料水を調製するに当たって、ポリカルボン酸類としてアクリル酸単独重合体（平均分子量：４５００、以下「Ａ−１」と略す）とアクリル酸／２−アクリルアミド−２−メチルプロパンスルホン酸／１−ブチルアクリルアミド共重合体（平均分子量：４５００、以下「Ａ−２」と略す）を、ポリカルボン酸類以外の化学発光原因物質としては、イソチアゾロン類である５−クロロ−２−メチル−３−イソチアゾロンと２−メチル−３−イソチアゾロンの８：２（重量比率）の混合物（以下「Ａ−３」と略す）を用いた。
【００５５】
ポリカルボン酸類とイソチアゾロン類とを純水に加えて、両水処理用薬品濃度を変えて一連の試料水を調製した。これらは、ポリカルボン酸類濃度が７．９ｐｐｍ（Ａ−１が２．２ｐｐｍ、Ａ−２が５．７ｐｐｍ）、イソチアゾロン類濃度が０．４３８ｐｐｍの試料水、ポリカルボン酸類濃度が１５．８ｐｐｍ（Ａ−１が４．４ｐｐｍ、Ａ−２が１１．４ｐｐｍ）、イソチアゾロン類濃度が０．８６５ｐｐｍの試料水、ポリカルボン酸類濃度が３１．６ｐｐｍ（Ａ−１が８．８ｐｐｍ、Ａ−２が２２．８ｐｐｍ）、イソチアゾロン類濃度が１．７５ｐｐｍの試料水であった。また、参照試料水として、純水の他に、上記の各試料水と同じポリカルボン酸類濃度のポリカルボン酸のみを含む一連の試料水、および、上記の各試料水と同じイソチアゾロン類濃度のイソチアゾロン類のみを含む一連の試料水も純水を用いて調製した。
【００５６】
インジェクター３から各試料水を１００μＬ（マイクロリットル、以下同様）ずつキャリア液中に注入し、試料酸化反応器５にて酸化処理を施した後、混合器６に導入した。
【００５７】
一方、ルテニウム錯体溶液としては、トリス（２，２’−ビピリジル）ルテニウム（II）塩酸塩を１０ミリモル／Ｌ（リットル、以下同様）濃度の硫酸水溶液に溶解させ、０．３ミリモル／Ｌの濃度に調製した溶液を用いた。このルテニウム錯体溶液を０．３ｍｌ／分で送液して試薬酸化反応器（電解酸化装置）４に供給し、１００μＡで連続的に定電流電解してＲｕ（II）をＲｕ(III) に酸化した。また、キャリア液としては純水を用い、０．５ｍｌ／分で送液した。
【００５８】
結果を図２、３、４に纏めた。図２は、ポリカルボン酸類とイソチアゾロン類の両方を含む一連の試料水についての化学発光強度と両水処理用薬品濃度の関係を示すグラフ図、図３は、ポリカルボン酸類のみを含む一連の試料水についての化学発光強度とポリカルボン酸類濃度の関係を示すグラフ図、図４は、イソチアゾロン類のみを含む一連の試料水についての化学発光強度とイソチアゾロン類濃度の関係を示すグラフ図である。これらの図で、「発光強度」は、各試料の化学発光強度測定値から純水の測定値をバックグラウンドとして差し引いた差分、即ち、補正値である。
【００５９】
図２〜４から明らかな様に、試料水を予め酸化することで、イソチアゾロン類に帰せられる化学発光強度を実質的に消去し、ポリカルボン酸類のみを選択的に検出できることが分かる。
【００６０】
実施例２
クーリングタワーと熱交換器を有する開放循環冷却水系のパイロットプラントの循環水にポリアクリル酸類「Ａ−１」と「Ａ−２」を循環水中の初期濃度が１０ｐｐｍ（Ａ−１が２．８ｐｐｍ、Ａ−２が７．２ｐｐｍ）となる様に、５−クロロ−２−メチル−３−イソチアゾロンと２−メチル−３−イソチアゾロンの８：２（重量比率）のイソチアゾロン類混合物及びイソチアゾロン類の安定剤としてのブロモニトロプロパノールを、循環水中の初期濃度がそれぞれ０．８ｐｐｍ及び１．０ｐｐｍとなる様に添加し、下記の条件で上記パイロットプラントを運転した。
水質：戸田工業用水
保有水量：２トン／分
循環水量：１トン
熱交換器の冷却水入口水温：２５℃
熱交換器の冷却水出口水温：３０℃
なお、蒸発水量と飛散水量に相当する量の戸田工業用水を補給して、循環水の濃縮倍数を約５倍に維持した。
【００６１】
循環水を定期的にサンプリングし、その試料水を実施例１と同様に処理して図２を検量線として用いた化学発光法及び鉄−チオシアネート比色法（特願平１０−１４８６１５号参照）により別々にポリアクリル酸類濃度を測定した。表１に経過日数に対する測定濃度値を示す。
【００６２】
【表１】

【００６３】
表１の結果から明らかな様に、化学発光法により求めたポリアクリル酸類濃度は鉄−チオシアネート比色法により求めたポリアクリル酸類濃度と良く一致しており、本発明の方法によれば循環水中にポリカルボン酸類とイソチアゾロン類が共存していても、循環水中のポリアクリル酸類の選択的定量を容易に行い、水処理用薬品の濃度管理が簡便に達成できることが確認できた。
【００６４】
【発明の効果】
本発明によれば、水処理用薬品の冷却水系における濃度管理方法において、スケール防止剤や分散剤や防食剤や凝集剤等として機能するポリカルボン酸類（または、更に必要に応じて殺菌剤やスライム防除剤等として機能するイソチアゾロン類）のそれ自体水処理用薬品の有効成分である検出対象薬品について、化学発光法により有効成分濃度を直接的に容易且つ迅速にしかも精度良く測定することができるので、得られた有効成分濃度値に基づいて、冷却水系のスケール防止や金属腐食防止等、並びに、殺菌やスライム防除等のための水処理用薬品の適正な濃度管理を行うことが可能となり、水処理用薬品濃度をほぼ最適有効濃度に維持することも可能で、スケール防止効果、金属腐食抑制効果、殺菌効果、スライム防除効果等の水処理用薬品の効果を良好に発揮させつつ冷却水系の運転を安定的に経済的且つ合理的に実施することができる。また、本発明に従った化学発光法によるポリカルボン酸類（または、更にイソチアゾロン類）の検出は、応答速度が早い（発光反応に要する時間が短い）ため、特に最近注目されている連続流れ分析法（ＦＩＡ： Flow Injection Analysis）に代表される全自動連続測定系を組み込んだ冷却水系の水処理用薬品の濃度管理方法への展開が可能である。
【図面の簡単な説明】
【図１】図１は、本発明において化学発光法を実施するための装置の一例を示すフロー図である。
【図２】図２は、実施例１におけるポリカルボン酸類とイソチアゾロン類の両方を含む一連の試料水についての化学発光強度と両水処理用薬品濃度の関係を示すグラフ図である。
【図３】図３は、実施例１におけるポリカルボン酸類のみを含む一連の試料水についての化学発光強度とポリカルボン酸類濃度の関係を示すグラフ図である。
【図４】図４は、実施例１におけるイソチアゾロン類のみを含む一連の試料水についての化学発光強度とイソチアゾロン類濃度の関係を示すグラフ図である。
【符号の説明】
１、２ ポンプ
３ インジェクター
４ 試薬酸化反応器
５ 試料酸化反応器
６ 混合器
７ 検出器
８ データプロセッサー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for controlling the concentration of water treatment chemicals (water treatment chemicals, water additive chemicals) in a cooling water system, and more specifically, a specific water treatment chemical added to a cooling water system having at least a cooling tower and a heat exchanger. The present invention relates to a method for performing stable and efficient concentration management of water treatment chemicals by a method of detecting and quantifying by a luminescence method.
[0002]
[Prior art]
Various water treatment chemicals are used in water treatment of at least open and closed cooling water systems having a cooling tower and a heat exchanger in order to prevent troubles caused by circulating water such as corrosion, scale, and slime. If there are obstacles such as those mentioned above, the pump power will increase, the heat transfer coefficient of the heat exchanger will decrease, the pipe will be blocked, the pipe and equipment will be corroded, the surrounding water will leak when the circulating water leaks, the product will be contaminated, Troubles such as sedimentation of sewage (sludge) occur. Generally, water treatment chemicals used in cooling water systems include anticorrosives, sludge dispersants, scale inhibitors, bactericides, slime control agents (slime control agents) and the like.
[0003]
In order to perform appropriate water treatment due to the effects of these various water treatment chemicals and maintain the effects of these water treatment chemicals in the cooling water system, the concentration of the water treatment chemical concentration in the circulating water of the cooling water system There is a lower limit and an optimum value, and therefore it is necessary to accurately grasp the concentration of these water treatment chemicals at an arbitrary position and time of the cooling water system and to perform appropriate concentration management.
[0004]
In a cooling water system, a water-soluble polymer is usually used as at least one component of a chemical for water treatment. Typical examples of such water-soluble polymers include polycarboxylic acids, which are used as scale inhibitors, dispersants, anticorrosives, cleaning agents, flocculants, and other functional agents.
[0005]
Among water treatment chemicals, the concentration of water-soluble polymers that function as dispersants, anticorrosives, flocculants, etc. is often difficult to measure because the concentration in water is quite low. Some types of water-soluble polymers are directly measured by colorimetric method, turbidimetric method, or other quantitative methods, but the concentration measurement operation is complicated or requires a long time. When it is impractical for the operation management of the cooling water treatment system because it cannot include the estimation and error by the experimenter or the adjustment of the amount of chemicals for water treatment corresponding to the change of the operating condition of the cooling water system There are many.
[0006]
For this reason, as a concentration management method in the case where it is impossible or difficult to measure the concentration of a water treatment chemical itself such as a water-soluble polymer, a substance that can be easily measured for concentration is widely used as a tracer. In other words, a method in which a tracer substance is added to and mixed with a water treatment chemical, the concentration of the tracer substance in the circulating water is measured, and the concentration of the water treatment chemical is indirectly measured (for example, bromine tracer method, lithium tracer method, fluorescence (Tracer method, dye tracer method).
[0007]
In addition, a tracer substance is combined with a water-soluble polymer, which is an effective chemical component, or the tracer substance is copolymerized at the time of polymerization, and the concentration of the tracer substance chemically bonded to the polymer molecule is measured and directly measured. A method for measuring the chemical concentration for water treatment has also been proposed. For example, a water-soluble polymer is fluorescently labeled with a fluorescent substance (fluorescent tracer such as naphthalene sulfonates) that is an inactive ingredient for water treatment chemicals, and this fluorescent substance is excited at an excitation wavelength, and fluorescence is emitted at the fluorescence wavelength. There are methods for controlling the concentration of chemicals for water treatment by measuring the strength (JP-A-4-233918, JP-A-4-326978, JP-A-5-163591, etc.).
[0008]
As another method, a method for detecting a water-soluble polymer such as polycarboxylic acid in a relatively simple manner using an immunoassay has been proposed (Japanese Patent Laid-Open No. 9-218199).
[0009]
In addition, various chemicals are used as a bactericidal agent and slime control agent in a cooling water system, and representative examples include isothiazolones. Because the concentration in the circulating water is quite low, there is no simple method for measuring the concentration, and detection is performed by a complicated and time-consuming method using high performance liquid chromatography (HPLC). ing. Thus, a method for detecting isothiazolones relatively easily using an immunoassay has been proposed (Japanese Patent Laid-Open No. 7-294522).
[0010]
[Problems to be solved by the invention]
Among conventional methods for measuring the concentration of water-soluble polymers, the colorimetric method, turbidimetric method, etc. are difficult to measure in the field, take a long time, or require a large-scale device for measurement. For this reason, there is a drawback that it takes a long time to obtain a measurement result after sampling a sample from circulating water. Therefore, the feedback information is provided after a long time has elapsed since the sample was sampled from the circulating water, and the amount of water treatment chemical consumed during that time is not included in the feedback information data. May have little value.
[0011]
In addition, the method of adding and mixing the tracer substance to the water treatment chemical can provide feedback information instantaneously, but the concentration management is performed based on the feedback information about the active ingredient as the water treatment chemical in the circulating water. However, it is not assumed that the active ingredient of the water treatment chemical is consumed, so there is a drawback that it may be different from the actual active ingredient concentration.
[0012]
The method of chemically binding a fluorescent tracer substance (fluorescent probe) to a water-soluble polymer molecule such as polycarboxylic acid is inferior in fluorescence analysis sensitivity, so the sensitivity is insufficient to detect a small amount of water-soluble polymer in circulating water. Since the fluorescence analysis method is inferior in selectivity, detection of water-soluble polymers is not only hindered by other components in the circulating water, but fluorescent tracer substances that are not components related to functions such as dispersants, anticorrosives, and flocculants are dissolved in water. Since it is further reacted with the water-soluble polymer, the cost is increased by the increase in the number of steps for manufacturing the water-soluble polymer water treatment chemicals, and the original function itself of the water-soluble polymer such as a dispersant, anticorrosive and flocculant May drop or disappear.
[0013]
In addition, a method for detecting a water-soluble polymer such as polycarboxylic acid using an immunoassay is not problematic in terms of sensitivity, but the measurement cost is high, and it is representative of continuous flow analysis (FIA: Flow Injection Analysis). However, it is difficult to apply to fully automatic continuous measurement.
[0014]
Concerning isothiazolones that function as bactericides and slime control agents in circulating water, as with HPLC method, the concentration management must be performed by a method that requires a lot of time and measurement costs. It is in trouble. The immunoassay method for isothiazolones has a high cost for measurement, and concentration control by fully automatic continuous measurement represented by continuous flow analysis is difficult.
[0015]
The present invention solves the above-mentioned problems of the prior art, and can quickly and accurately measure the concentration of active ingredients in the circulating water of the cooling water system, and also can monitor the chemical concentration management method for water treatment. The purpose is to provide.
[0016]
[Means for Solving the Problems]
  That is, the present invention is a kind of chemical for water treatment existing in circulating water after pre-oxidizing a circulating water sample in a cooling water system having at least a cooling tower and a heat exchanger.It is at least one of the group consisting of homopolymers, copolymers, and salts thereof composed of polymerizable monomers having a carboxylic acid group and an unsaturated double bondThe concentration of polycarboxylic acidsOxidizing the complex of transition metal element and nitrogen-containing aromatic ligand and / or ammonium nitrate of rare earth element to increase the oxidation number of transition metal element and / or rare earth element, Chemiluminescence is caused by bringing the circulating water into contact with a pre-oxidized sample.The present invention provides a method for managing the concentration of a chemical for water treatment in a cooling water system, comprising a step of measuring by a chemiluminescence method. If a sample (analyte) of circulating water is measured by chemiluminescence without oxidizing it in advance, not only polycarboxylic acids but also other water treatment chemicals such as isothiazolones act as chemiluminescence-causing substances in the measurement. In this case, the sample of the circulating water is oxidized in advance to oxidize and decompose other water treatment chemicals such as isothiazolones, so that it does not substantially act as a chemiluminescent substance. The present inventors have found that not only it can act as a chemiluminescence-causing substance even after oxidation, but also the chemiluminescence intensity attributed to polycarboxylic acids can be extremely high depending on the oxidation reaction conditions. The invention has been completed.
[0017]
When the circulating water further contains isothiazolones as other types of water treatment chemicals, the total concentration of isothiazolones + polycarboxylic acids is measured by the chemiluminescence method without previously oxidizing the circulating water sample in the method of the present invention. Further steps can be included. This is because the chemiluminescence intensity of the isothiazolones by the chemiluminescence method of the isothiazolones is much higher than the polycarboxylic acids without pre-oxidation at various chemical concentrations in the circulating water of the general cooling water system. This is because it can be determined from the total concentration. Therefore, in this case, more appropriate concentration management can be performed for the two types of water treatment chemicals.
[0018]
  The chemiluminescence method used in the method of the present invention is:, TransitionOxidizing a complex of a transfer metal element and a nitrogen-containing aromatic ligand and / or an ammonium nitrate of a rare earth element to increase the oxidation number of the transition metal element and / or rare earth element, In this method, a sample of circulating water containing polycarboxylic acids (or further isothiazolones) or a pre-oxidized sample is contacted to cause chemiluminescence. ThisConversionIn the chemiluminescence method, if a sample of circulating water containing both polycarboxylic acids and isothiazolones is subjected to measurement without being oxidized beforehand, there is no selectivity between the polycarboxylic acids and isothiazolones that are chemiluminescence-causing substances. Therefore, in the circulating water containing both, the chemiluminescence intensity of the sample appears as the sum of the chemiluminescence intensity of the polycarboxylic acids and the chemiluminescence intensity of the isothiazolones, but the latter intensity value is overwhelming as described above. Big.
[0019]
In the present invention, for example, based on the measured concentration value of polycarboxylic acids, which are water treatment chemicals to be detected by the chemiluminescence method, the required amount of water treatment chemicals is added to and supplemented to the cooling water system. It is possible to control the concentration of water treatment chemicals in the cooling water system. To that end, for example, by monitoring the concentration of polycarboxylic acids, which are active ingredients themselves in the water treatment chemicals in the cooling water system, in the circulating water of the cooling water system by the chemiluminescence method according to the present invention, In order to maintain the concentration of water treatment chemicals such as polycarboxylic acids in circulating water at a level sufficient to exert effects such as scale prevention and metal corrosion prevention, for example, the required amount of water treatment chemicals as necessary It is also possible to adopt a control method of adding and replenishing to the cooling water system. In this case, in the case of controlling the concentration and replenishment amount of chemical components for water treatment such as anticorrosives and bactericides other than polycarboxylic acids, the polycarboxylic acids will be used as a kind of tracer, For example, each chemical component for water treatment other than polycarboxylic acids is added and replenished in an amount proportional to the amount of polycarboxylic acids added and replenished. The water treatment chemical can also be in the form of a water treatment chemical blended product containing various chemical components including polycarboxylic acids. In this case, addition of water treatment chemicals other than polycarboxylic acids. Calculation of the replenishment amount can be omitted. Here, since polycarboxylic acids are different from those chemically bonded to the aforementioned fluorescent tracer substance, the effects as scale inhibitors, dispersants, anticorrosives, flocculants, etc. can be reduced, and water-soluble polymer water can be used. There is no increase in manufacturing costs due to the extra steps of manufacturing the processing chemicals.
[0020]
In a cooling water system that also contains isothiazolones in addition to polycarboxylic acids, a combination of both the measured concentration value of polycarboxylic acids and the total measured concentration value of polycarboxylic acids + isothiazolones by the above-described method can be used for more appropriate water. It is also possible to control the concentration of processing chemicals. As described above, according to the method of the present invention, the concentration of polycarboxylic acids, which are active ingredients of water treatment chemicals in circulating water, can be directly and accurately measured and confirmed. It is possible to easily manage the appropriate concentration of the chemical, and it is also possible to more appropriately manage the chemical concentration for water treatment by using the total measured concentration value as necessary.
[0021]
In the present invention, a sample of circulating water sampled from the cooling water system is oxidized in advance and subjected to measurement by a chemiluminescence method to determine the concentration of polycarboxylic acids. More specifically, for example, the concentration of polycarboxylic acids is calculated by comparing the measured value of the chemiluminescence intensity of a previously oxidized sample with a calibration curve prepared in advance. In general, the actual sample water itself is oxidized in advance to measure the chemiluminescence intensity. However, if necessary, the diluted solution, concentrated solution or purified solution of the actual sample water is oxidized in advance to increase the chemiluminescence intensity. The concentration of polycarboxylic acids can also be calculated by measurement. In the case of circulating water containing polycarboxylic acids and isothiazolones, when the sample is further subjected to chemiluminescence measurement without being oxidized in advance, it is substantially the same as described above except that the sample is not oxidized in advance. Are the same.
[0022]
Examples of the transition metal element in the complex of a transition metal element and a nitrogen-containing aromatic ligand that can be used as a detection reagent (chemiluminescent substance) in the present invention include, for example, ruthenium, iridium, chromium, cobalt, iron, rhodium, Examples include osmium. Among these, particularly preferred transition metal elements are ruthenium and osmium in terms of low toxicity and high luminous efficiency. On the other hand, examples of the nitrogen-containing aromatic ligand include bipyridine, bipyrazine, phenanthroline, and derivatives thereof. The derivative as used herein refers to a derivative in which at least one hydrogen atom directly bonded to a carbon atom in a pyridine ring or a pyrazine ring in bipyridine, bipyrazine, or phenanthroline is substituted with another substituent. Examples of such substituents include a methyl group, a phenyl group, a vinyl group, a carboxyl group, a carboxylic ester group, a sulfate group, a sulfate amide group, a hydroxyl group, an amino group, an amide group, an ammonium group, and a pyridinium group. It is done. Some specific examples of nitrogen-containing aromatic ligands include 2,2'-bipyridine, 2,2 ', 5,5'-bipyrazine, 1,10-phenanthroline, bathophenanthroline, 4,4'-di Carboxy-2,2′-bipyridine and its salts, mono- and di-alkyl esters of 4,4′-dicarboxy-2,2′-bipyridine and their salts, 4,4′-dicarboxy-2,2 '-Bipyridine mono- and di-N-hydroxysuccinimide and salts thereof, 4,4'-disulfonic acid-2,2'-bipyridine and salts thereof, 4-methyl-4'-vinyl-2,2'- Bipyridine and its homopolymers and copolymers, 4-chloromethyl-4′-methyl-2,2′-bipyridine, 4,4′-di (chloromethyl) -2,2′-bipyridine, bathophenanthroline disulfo Acid and salts thereof. Of these, particularly preferred nitrogen-containing aromatic ligands are 2,2'-bipyridine and 1,10-phenanthroline.
[0023]
  In addition, as the ammonium nitrate of rare earth elements that can be used as a detection reagent (chemiluminescent substance) in the present invention, scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, Examples thereof include ammonium nitrates of holmium, erbium, thulium, ytterbium, and lutetium. Among these, particularly preferred compounds are diammonium cerium (III) nitrate and diammonium cerium (IV) nitrate. Diammonium cerium (IV) nitrate is a compound that has already been oxidized to increase its oxidation number, but is relatively stable and can be used as it is as an oxidant. The above according to the present inventionWhoThe method includes a step of oxidizing a complex of a transition metal element and a nitrogen-containing aromatic ligand and / or an ammonium nitrate salt of a rare earth element to increase the oxidation number of the transition metal element and / or rare earth element. In the case of diammonium cerium (IV), instead of performing this step at the detection work site, the reagent manufacturer simply performs this step.
[0024]
Regarding the light emission mechanism of chemiluminescence used in the present invention, a tris (2,2′-bipyridyl) ruthenium (II) complex is used as a chemiluminescent substance, and a polycarboxylic acid that has been previously oxidized is used as a chemiluminescent causative substance. Will be described as an example. Ruthenium divalent tris (2,2′-bipyridyl) ruthenium (II) complex undergoes oxidation, and ruthenium becomes trivalent tris (2,2′-bipyridyl) ruthenium (III) complex, which is previously oxidized. It is considered that an excited divalent complex is generated by the energy of the chemical reaction and is generated by the energy of the chemical reaction, and excessive energy is emitted as light emission when this becomes a divalent complex in the ground state. When the chemiluminescent material is cerium ammonium nitrate, it is the same as described above, except that oxidation and reduction between trivalent cerium (III) and tetravalent cerium (IV) is utilized. The emission wavelength at this time is around 610 to 620 nm in the case of ruthenium, and around 550 nm in the case of cerium. In addition, isothiazolones that have not been subjected to pre-oxidation treatment are the same as described above except that they themselves act as chemiluminescence-causing substances. Hereinafter, a ruthenium complex will be mainly described as a representative example of a transition metal complex, and an ammonium nitrate salt of cerium will be mainly described as a representative example of an ammonium nitrate salt of a rare earth element, but the present invention is of course not limited thereto. Note that an increase in sensitivity (sensitization action) is expected by the combined use of a ruthenium complex and an ammonium nitrate salt of cerium, and the same effect is expected with a combination of other plural chemiluminescent substances.
[0025]
As is apparent from the above, when polycarboxylic acids (or further isothiazolones) are to be detected according to the present invention, it is necessary to make ruthenium or cerium into an oxidized state (valence) by oxidation. It is. Several methods are known for this ruthenium or cerium oxidation method. For example, a method of oxidizing ruthenium using an oxidizing agent [using a metal oxide such as lead dioxide, bismuth oxide, and gold oxide as the oxidizing agent, filling the column with the metal oxide, and passing the ruthenium complex through the column. Oxidation method (JP-A-5-302895), potassium peroxodisulfate as an oxidant as an aqueous solution, and photochemical oxidation by irradiating light such as ultraviolet rays in the coexistence of this oxidant and ruthenium complex (S. Yamazaki et al., High Resol. Chromatogr.,twenty one315-316, 1998), using a solid oxidant with a semiconductor photocatalyst immobilized on a carrier as an oxidant, photochemically oxidized by irradiating light such as ultraviolet rays in a state where this oxidant is in contact with a ruthenium complex. And a method of oxidizing ruthenium electrochemically on the electrode (JP-A-5-52755) and the like. In the present invention, when the detection reagent is used, there is no particular limitation on the oxidation method of ruthenium or cerium, and any oxidation method may be used. However, in order to achieve long-term continuous automatic operation of the apparatus for performing the chemiluminescence method, a method of electrochemically ruthenium oxidation on the electrode or a semiconductor photocatalyst immobilized as an oxidizing agent on the support A method in which a solid oxidizing agent is used and photochemical oxidation is performed by irradiation with light such as ultraviolet rays in a state where the oxidizing agent is in contact with a ruthenium complex or an ammonium nitrate salt of cerium. Note that a relatively stable diammonium cerium (IV) nitrate can be used from the beginning instead of diammonium cerium (III) nitrate as a detection reagent, and in this case, an oxidation step is unnecessary.
[0026]
Thus, in order for the ruthenium complex and the ammonium nitrate of cerium to emit light, it is important to generate an activated species in an excited state, and (pre-oxidized) polycarboxylic acids (and unoxidized isothiazolones) Is efficiently involved in the formation of active species in the excited state, and thus detection with high sensitivity becomes possible. On the other hand, many organic reducing substances and inorganic salts (pre-oxidized) react with, for example, a ruthenium complex or ammonium nitrate of cerium, but no active species (complex etc.) in an excited state are formed. Not shown. Therefore, the above-described chemiluminescence method that can be used in the present invention can detect polycarboxylic acids (and unoxidized isothiazolones) that are highly sensitive and selectively pre-oxidized, and can control the concentration of water treatment chemicals in the cooling water system. Can be carried out effectively.
[0027]
In addition, tris (2,2′-bipyridyl) ruthenium (III) and the like obtained by the above oxidation is unstable in an aqueous medium. It is necessary to perform a chemiluminescent reaction with the substance.
[0028]
The method for oxidizing the sample of circulating water that can be used in the present invention is not particularly limited as long as the sample is oxidized to a desired degree and polycarboxylic acids can be selectively detected. For example, a method of oxidizing using an oxidizing agent. [Use a metal oxide such as lead dioxide, bismuth oxide, gold oxide as an oxidant and oxidize by contacting the metal oxide with a sample, or use sodium bromate or potassium bromate as an oxidant. Using a method of photochemical oxidation by irradiating light such as ultraviolet rays with the oxidant in contact with the sample, or using a solid oxidant with a semiconductor photocatalyst immobilized on the carrier as the oxidant, (A method of photochemical oxidation by irradiating light such as ultraviolet rays in a contact state, a method of using a lead dioxide / sulfuric acid aqueous solution as an oxidizing agent, and contacting this oxidizing agent with a sample in a homogeneous system to oxidize) On the electrode Chemical methods such as oxidation of the sample and the like. Oxidation reaction conditions (temperature, time, pH, oxidant amount, (light irradiation amount), etc.) vary greatly depending on the oxidation method, and cannot be specified in general.
[0029]
In this invention, the method of oxidizing sample water with the sample oxidation apparatus using a solid oxidizing agent is employ | adopted preferably. Examples of the solid oxidizing agent that can be used include a solid oxidizing agent in which a metal oxide such as lead dioxide, bismuth oxide, and gold oxide or a semiconductor photocatalyst is immobilized on a carrier. Metal oxides such as lead dioxide, bismuth oxide, and gold oxide are consumed over long-term use, whereas solid oxidizers with a semiconductor photocatalyst immobilized on a carrier are preferably used because the catalyst is regenerated by light irradiation. It is done. When an oxidant with a semiconductor photocatalyst immobilized on a carrier is used as the solid oxidant, the oxidation method is photochemical oxidation by irradiating light such as ultraviolet rays with the oxidant in contact with a sample of circulating water. It becomes the method to do. Examples of the light source used in the photochemical oxidation include not only an ultraviolet lamp but also a black light (far ultraviolet source), a general fluorescent lamp, and sunlight. A solid oxidant with such a semiconductor photocatalyst immobilized on a carrier is easier to handle than oxidants such as sodium bromate, potassium bromate and lead dioxide / sulfuric acid, and can be separated from the sample. Furthermore, since the catalyst is regenerated by light irradiation, unlike the case of metal oxide-based oxidants such as lead dioxide, bismuth oxide, gold oxide, etc., there is no exhaustion of the oxidant itself, and periodic oxidant replacement is substantially performed. It is preferable in that it is not required or is very low in frequency. On the other hand, the method of electrochemically oxidizing a sample on an electrode is preferable in that continuous automatic operation can be performed as described above, but there is a concern about problems such as electrode contamination when continuously operated for a long period of time. In view of the above, it is particularly advantageous to use a solid oxidizing agent having a semiconductor photocatalyst immobilized on a support.
[0030]
The solid oxidizing agent having a semiconductor photocatalyst immobilized on a carrier is, for example, a photocatalyst carrier (Japanese Patent Application No. 11-143958) carrying various semiconductor photocatalysts on various carriers. In such a photocatalyst carrier, examples of the semiconductor photocatalyst include titanium oxide, strontium titanate, zinc oxide, iron oxide, zirconium oxide, niobium oxide, tungsten oxide, tin oxide, cadmium sulfide, cadmium selenide, molybdenum sulfide, Examples of the carrier include glass plates, glass balloons, glass beads, glass fibers, paper, plates of various resins such as polyolefin, nylon, and fluorine resins, fibers, pipes, powders, and granular materials. However, it is not particularly limited as long as it can be separated from the sample. However, from the viewpoint of ease of preparation of the solid oxidant having the semiconductor photocatalyst immobilized on the carrier and ease of handling and stability in the liquid, the polyolefin as the carrier was supported with titanium oxide as the semiconductor photocatalyst. A photocatalyst carrier is preferred as the solid oxidant, and its shape varies depending on the form of the oxidation reaction, but is generally preferably granular.
[0031]
Further, the amount of the semiconductor photocatalyst supported on the carrier is not particularly limited as long as the desired oxidation reaction can proceed, but in general, it can be selected in the range of 1 ppm to 50% by weight with respect to the total amount of carrier + photocatalyst. . In addition, as a form of carrying the semiconductor photocatalyst on the carrier, a form in which the semiconductor photocatalyst is carried near the outermost layer of the carrier is preferable, and further, from a form in which the particles of the semiconductor photocatalyst are carried on the outermost layer of the carrier in a single layer. However, it is preferable to have a configuration in which multiple layers are supported near the outermost layer.
[0032]
The oxidation reaction in this case may be performed under any conditions (temperature, time, pH, solid oxidant amount, light irradiation amount, etc.) as long as the desired oxidation of the sample of circulating water is achieved. The degree of progress of the oxidation reaction affects the degree of oxidation of polycarboxylic acids and changes the intensity of chemiluminescence, so a series of similar types of cooling, such as monitoring the concentration of polycarboxylic acids at a fixed point (predetermined measurement location), etc. It is necessary to apply certain oxidation conditions to samples of circulating water in the water system. In addition, even in the case of circulating water samples of the same cooling water system, the chemiluminescence intensity changes depending on the progress of the oxidation reaction. Therefore, prior to measurement, the oxidation reaction conditions are changed to selectively select polycarboxylic acids. If conditions for obtaining detection are set, analysis with higher accuracy can be performed. The reaction conditions cannot be specified unconditionally as described above. For example, the higher the reaction temperature (for example, 70 to 80 ° C.), the shorter the reaction time (for example, around 10 seconds). The pH is also not limited, but basic conditions are generally preferred over acidic conditions. The reaction method is not particularly limited, and may be a continuous method in which the sample is continuously brought into contact with the solid oxidant in a column or the like, or a batch method in which the solid oxidant is brought into contact with the sample in a container. .
[0033]
The polycarboxylic acids that can be detected chemicals in the present invention are homopolymers and copolymers composed of a polymerizable monomer having a carboxylic acid group and an unsaturated double bond, and salts thereof. Some examples of such polymerizable monomers include acrylic acid, methacrylic acid, vinyl acetic acid, crotonic acid, maleic acid, itaconic acid, mesaconic acid, fumaric acid, citraconic acid, 1,2,3,6- Tetrahydrophthalic acid and their alkali metal salts, alkaline earth metal salts, ammonium salts, maleic anhydride, 1,2,3,6-tetrahydrophthalic anhydride, 3,6-epoxy-1,2,3 , 6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, bicyclo [2.2.2] -5-octene-2,3-dicarboxylic anhydride, 3-methyl-1, Examples include 2,6-tetrahydrophthalic anhydride, 2-methyl-1,3,6-tetrahydrophthalic anhydride. Of these polymerizable monomers, acrylic acid, methacrylic acid, and maleic anhydride are particularly preferable.
[0034]
The polycarboxylic acids that can be detected chemicals in the present invention contain less than 80% by weight of a polymerizable monomer unit that does not contain a carboxylic acid group but has an unsaturated double bond as long as the polymer is water-soluble. May be included. Some examples of such polymerizable monomers include esters of acrylic acid or methacrylic acid with alkyl having 1 to 4 carbon atoms (specific examples include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl Methacrylate, butyl methacrylate, isobutyl methacrylate, etc.), hydroxyalkyl esters of acrylic acid or methacrylic acid (specific examples are hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, etc.), other acrylic acid or methacrylic acid (Specific examples include 2-sulfoethyl acrylate, 3-sulfopropyl acrylate, 2-sulfatoethyl acrylate, 2-N, N-dimethylaminoethyl Acrylate, 2-sulfoethyl methacrylate, 3-sulfopropyl methacrylate, 2-sulfatoethyl methacrylate, phosphoethyl methacrylate, ethylene glycol diacrylate, trimethylolpropane triacrylate, etc.), unsubstituted and substituted (meth) acrylamide (specific) Examples include acrylamide, methacrylamide, Nt-butylacrylamide, N-methylacrylamide, N, N-dimethylacrylamide, 3-N, N-dimethylaminopropylacrylamide, acrylamide glycolic acid, etc.), (meth) acrylonitrile ( Specific examples include acrylonitrile and methacrylonitrile), sulfonic acid group-containing monomers (specific examples include allyl sulfonic acid, vinyl sulfonic acid, p-styrene sulfonic acid, 2-acrylic acid, Rilamide-2-methylpropanesulfonic acid, methallylsulfonic acid, 1-allyloxy-2-hydroxypropylsulfonic acid, etc.), phosphonic acid group-containing monomers (specific examples include allylphosphonic acid, vinylphosphonic acid, etc.), Other monomers (specific examples include allyl alcohol, 2-vinylpyridine, 4-vinylpyridine, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, N-vinylimidazole, N-vinylimidazoline, 2 -Vinylimidazole, 2-vinylimidazoline, N-acryloylmorpholine, acrolein, diallyl phthalate, vinyl acetate, styrene, etc.), and monomers capable of forming a salt among the above monomers are alkali metal salts thereof. , Alkaline earth metal salts, ammonium salts and the like.
[0035]
The molecular weight of the polycarboxylic acids that can be detected in the present invention is not particularly limited, but a polymer in the range of 500 to 20000000 can be detected. Moreover, these polycarboxylic acids may be used individually by 1 type, and may mix and use 2 or more types.
[0036]
The isothiazolones that can be used as a chemical to be detected and whose concentration is roughly determined by applying a chemiluminescence method in a non-oxidized state of a sample of circulating water in the present invention are compounds having a structure represented by the formula “Chemical Formula 1”. is there.
[0037]
[Chemical 1]

[0038]
[In the formula, R¹, R²Are independently hydrogen, halogen, or an alkyl group having 1 to 4 carbon atoms, or together, form a saturated, unsaturated or aromatic 5- or 6-membered ring, and Y is Hydrogen, unsubstituted or halogen-substituted alkyl group having 1 to 18 carbon atoms, unsubstituted or halogen-substituted alkenyl group having 2 to 8 carbon atoms, unsubstituted or halogen-substituted alkynyl group having 2 to 8 carbon atoms, carbon number Unsubstituted or halogen-substituted cycloalkyl group having 3 to 8, unsubstituted up to 10 carbon atoms, halogen-substituted, alkyl (alkyl group has 1 to 4 carbon atoms) substituted or alkoxy (alkoxy group has 1 carbon atom) -4 substituted) aralkyl group, unsubstituted up to 10 carbon atoms, halogen substituted, alkyl (alkyl group has 1 to 4 carbon atoms) substituted or alkoxy (alkoxy group carbon) The number is a group selected from 1-4 and is) substituted aryl group. ]
[0039]
Some specific examples of the substituent Y include methyl, ethyl, propyl, butyl, hexyl, octyl, cyclohexyl, 4-methoxyphenyl, 4-chlorophenyl, 3,4-dichlorophenyl, benzyl, 4-methoxybenzyl, 4-chlorobenzyl, phenethyl, 4-phenylbutyl, chloromethyl, chloropropyl, hydrogen and the like can be mentioned.
[0040]
Some specific examples of isothiazolones that can be detected chemicals in the present invention include 2-methyl-3-isothiazolone, 5-chloro-2-methyl-3-isothiazolone, 4,5-dichloro-2-n- Examples include octyl-3-isothiazolone. These isothiazolones may be used alone or in combination of two or more.
[0041]
The measurement conditions (chemiluminescence reaction conditions) for detecting pre-oxidized polycarboxylic acids (or unoxidized polycarboxylic acids + isothiazolones) in the method of the present invention are not particularly limited, and the measurement temperature, pH The concentration of the sample water can be arbitrarily set. However, since the detection sensitivity of such a detection target substance is affected by the measurement temperature and pH, it is desirable to perform measurement under constant measurement conditions.
[0042]
Water treatment chemicals to be added to the cooling water system include, for example, dispersants such as polycarboxylic acids and other water-soluble polymers (some of which also function as anticorrosives, flocculants, etc.), phosphonic acids, and phosphoric acid. Anticorrosives such as salt, silicate, nitrite, tungstate, boric acid, zinc salt, aromatic carboxylate, sulfite, hydrazine, tannin, lignin, lignin sulfonate, sodium ascorbate, sodium ersorbate, glucose Sterilization and killing of azole copper anticorrosives such as benzotriazole, tolyltriazole, mercaptobenzothiazole, ammonium compounds, amine compounds, chlorine compounds, bromine compounds, and organic nitrogen sulfur compounds such as isothiazolones Algae can be mentioned. In the method of the present invention, polycarboxylic acids that can be detected chemicals and other water treatment chemicals such as isothiazolones can be used in combination or mixed together. By monitoring the concentration of carboxylic acids, it is possible to control the concentration of the water treatment chemicals in the cooling water system by controlling the amount of addition and replenishment of these water treatment chemicals.
[0043]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to such embodiments.
[0044]
In the method for controlling the concentration of a cooling water system water treatment chemical of the present invention, a calibration curve for polycarboxylic acids is prepared in advance. Such a calibration curve is created by measuring the chemiluminescence intensity of blank water containing no polycarboxylic acids and several control waters of different known polycarboxylic acid concentrations. These blank water and control water are also oxidized in advance under the same oxidation reaction conditions as when the sample of circulating water is previously oxidized, and the chemiluminescence intensity is measured. Of course, it is preferable that the blank water does not contain only polycarboxylic acids and other components (for example, impurity components and other water treatment chemicals) use the same blank water in terms of measurement accuracy.
[0045]
Polycarboxylic acids, which are detection target chemicals, can be detected with sufficient sensitivity by chemiluminescence using ordinary circulating water as is, but chemiluminescence is performed after dilution, concentration, or purification as necessary. You may use for the detection by a method. For example, when the circulating water contains both polycarboxylic acids and isothiazolones, as an example of the purification operation for separately detecting them, the pH of the sample is adjusted as necessary (for example, for the sample of circulating water) , PH 2 to 3), selective adsorption of polycarboxylic acids to the adsorbent gel, elution, etc., and the resulting polycarboxylic acid-containing eluate (purified solution) is pre-oxidized to produce a chemiluminescence method Then, the amplified chemiluminescence intensity is measured, and the measured value is converted into the initial concentration of polycarboxylic acids in the cooling water system, and the quantification can be performed (see US Pat. No. 4,514,504). In this case, the analysis accuracy and stability can be improved, and the polycarboxylic acids can be concentrated through the above treatment operation when the concentration of the polycarboxylic acids in the circulating water of the cooling water system is particularly low. On the other hand, the isothiazolone-containing eluate (purified solution) obtained by the above-mentioned treatment operation is measured in advance by chemiluminescence intensity without being oxidized, and the measured value is converted into the initial concentration of isothiazolones in the cooling water system. Quantification can be performed with high accuracy. However, this operation is complicated and requires time and labor. However, the implementation of this method is still an implementation of the present invention.
[0046]
Next, an example of an apparatus for carrying out a preferred chemiluminescence method in the present invention will be described. The apparatus basically includes a pump for feeding a carrier liquid, an injector for injecting a sample of circulating water containing polycarboxylic acids (or further isothiazolones) into the carrier liquid, a ruthenium complex and / or an ammonium nitrate salt of cerium, etc. A pump for feeding a solution containing a detection reagent, a sample oxidation reactor for oxidizing a sample in advance, a reagent oxidation reactor for oxidizing a detection reagent such as ruthenium complex and / or ammonium nitrate of cerium, a carrier liquid and a sample Mixers that mix solutions of detection reagents such as oxidized mixed water and oxidized ruthenium complex and / or oxidized ammonium nitrate of cerium, detectors that detect chemiluminescence, and data obtained by the detector Consists of data processor to record. However, in some cases, the circulating water sample may be oxidized in advance and injected into the carrier liquid, or the circulating water sample itself may be supplied continuously and the carrier liquid may not be used. In this system, the injector is unnecessary. In addition, the mixer may be an in-line mixer, a mixing coil, etc., and the mixture after mixing is desired to be immediately used for detection. Therefore, a mixer is attached to the detector, or stirring and mixing are performed in the detector. A detector configured to perform mixing and mixing may also serve as a mixer. The data processor is configured to take the chemiluminescence intensity output from the detector as an electrical signal, record the data, and record and display the data by converting it to a polycarboxylic acid concentration as necessary. Is preferred. Such a data processor preferably includes a calibration curve of chemiluminescence intensity versus polycarboxylic acid concentration, and can perform arithmetic processing such as polycarboxylic acid concentration calculation, and further activate the reagent supply pump as necessary. Preferably, an output signal for stopping can also be generated.
[0047]
As the above reagent oxidation reactor, different reactors are used depending on the oxidation method for oxidizing the detection reagent such as ruthenium complex and / or ammonium nitrate of cerium. For example, when a metal oxide such as lead dioxide, bismuth oxide or gold oxide is used as the oxidizing agent, a column filled with this metal oxide is used as the reactor. In addition, when using a solid oxidizing agent such as potassium peroxodisulfate or a semiconductor photocatalyst immobilized on a carrier as an oxidizing agent, such an oxidizing agent and a detection reagent such as ruthenium complex and / or ammonium nitrate of cerium coexist. An apparatus that can be photochemically oxidized by irradiating light such as ultraviolet rays under the condition is used as the reactor. In this case, as a light source, a general fluorescent lamp or sunlight can be used in addition to an ultraviolet lamp or a black light. On the other hand, when a method for electrochemically oxidizing a detection reagent such as a ruthenium complex and / or ammonium nitrate of cerium on an electrode is employed, an electrolytic oxidation apparatus equipped with a stabilized DC power source is used as a reactor. However, when diammonium cerium (IV) nitrate is used as a detection reagent, a reagent oxidation reactor is not required. In addition, since the oxidized reagent is unstable, the reagent oxidation reactor is basically an oxidation reactor in which the reagent can be supplied and discharged in a very short time and in which oxidation proceeds continuously.
[0048]
On the other hand, the sample oxidation reactor is preferably a sample oxidation apparatus that oxidizes a sample of circulating water using a solid oxidizing agent. Examples of solid oxidizers that can be used include metal oxides such as lead dioxide, bismuth oxide, and gold oxide, and solid oxidizers in which a semiconductor photocatalyst is immobilized on a carrier, but metals such as lead dioxide, bismuth oxide, and gold oxide. Since oxides are consumed over a long period of use, a solid oxidant in which a semiconductor photocatalyst regenerated by irradiation with light is immobilized on a carrier is preferably used. When an oxidant with a semiconductor photocatalyst immobilized on a carrier is used as the solid oxidant, the oxidation method is photochemical oxidation by irradiating light such as ultraviolet rays with the oxidant in contact with a sample of circulating water. It becomes the method to do. To give a specific example of a sample oxidation reactor, if you want to perform an oxidation reaction continuously, the reaction is configured to fill the column with metal oxides such as lead dioxide, bismuth oxide, and gold oxide, and then flow the sample through the column. The reactor can be used to irradiate light to the column while filling the column with a solid oxidizer with a vessel or semiconductor optical butterfly immobilized on the carrier, and flowing the sample through the column. If it is desired to carry out the test, a reactor in which a metal oxide such as lead dioxide, bismuth oxide, or gold oxide can be brought into contact with the sample in the vessel or a solid oxidant in which the semiconductor photocatalyst is immobilized on the carrier in the sample. And a reactor that can irradiate the container with light.
[0049]
FIG. 1 is a flowchart showing an example of such an apparatus. Solutions containing a carrier liquid and a ruthenium complex and / or an ammonium nitrate salt of cerium (in FIG. 1, this solution is represented by “Ru complex solution”) are supplied by pumps 1 and 2, respectively. In addition, when a water-soluble oxidant such as potassium peroxodisulfate is used as an oxidant for the reagent and photochemical oxidation is performed, the oxidant is added in advance to a solution containing a ruthenium complex and / or an ammonium nitrate salt of cerium. It is desirable to keep it. A solution containing a ruthenium complex and / or an ammonium nitrate salt of cerium is continuously oxidized in the reagent oxidation reactor 4 and supplied to the mixer 6. On the other hand, a certain amount of circulating water sample containing polycarboxylic acids is injected into the carrier liquid from the injector 3, and is continuously oxidized in the sample oxidation reactor 5 and supplied to the mixer 6. In the mixer 6, an oxidized mixed water of the carrier liquid and the sample and an oxidized ruthenium complex and / or a solution of ammonium nitrate of cerium are mixed and reacted to cause chemiluminescence. This chemiluminescence is detected by a detector 7 installed immediately after the mixer 6, and the chemiluminescence intensity and the polycarboxylic acid concentration conversion value are recorded in the data processor 8. The data processor 7 generally includes an A / D converter, a computer, and a display device (CRT, liquid crystal display, recorder, etc.).
[0050]
As described above, the concentration measurement procedure for polycarboxylic acids according to the present invention is usually simple, and the measured values can be obtained quickly with good reproducibility. Can do. In other words, the concentration of the water treatment chemical is controlled by batch-feeding the insufficient amount of the water treatment chemical based on the measured value of the polycarboxylic acid concentration by the chemiluminescence method according to the present invention or by injecting the water treatment chemical. The pump stroke is adjusted, for example, continuously injected into the lower water tank of the cooling tower. In addition, by installing a chemiluminescence analyzer (for example, the device of FIG. 1) as an online device, converting an output signal from the analyzer into an operation output by a conversion unit, and operating a water treatment chemical injection pump, It is also possible to automatically control the concentration of water treatment chemicals. In this way, a concentration equal to or higher than the lower limit concentration (limit concentration) at which the water treatment chemical exhibits an effect, preferably, an optimum concentration is maintained in the circulating water. Water treatment chemicals are administered in the form of “basic input” in which a large amount of water treatment chemicals (especially anticorrosives) are administered at the start of operation after long-term shutdown of the cooling water system, and chemicals in the system during normal operation of the cooling water system There is “holding in” which compensates for the decrease in the chemical concentration in the circulating water due to the consumption, scattering and forced blow of water, but the present invention can be applied in any case.
[0051]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples.
[0052]
The polycarboxylic acids were selectively detected by the chemiluminescence method according to the present invention using the apparatus shown in FIG. As the reagent oxidation reactor 4 in FIG. 1, an electrolytic oxidation apparatus (commercial name “Comet 2000”, manufactured by Comet Co., Ltd.) was used.
[0053]
In addition, the sample oxidation method uses a solid oxidant in which a semiconductor photocatalyst is immobilized on a carrier as an oxidant, and photochemically oxidizes by irradiating far ultraviolet rays while the sample is in contact with the sample. Was used. As the sample oxidation reactor 5 in FIG. 1, one having the following structure was used. That is, this solid oxidizing agent is mixed with titanium oxide (made by Degussa, Germany, trade name “P25”) as a semiconductor photocatalyst and high density polyethylene pellets (trade name “Nipolon Hard 2500” made by Tosoh Corporation) as a carrier. It was prepared by heating and stirring and heat-sealing to form titanium oxide-supported polyethylene granules (titanium oxide support: 3% by weight). The titanium oxide-supported polyethylene granules were packed in a Teflon tube, The sample oxidation reactor was configured with the tube wrapped around black light (wavelength: 352 nm). In this state, the sample was oxidized photochemically by irradiating far ultraviolet rays. The oxidation reaction time was 10 seconds.
[0054]
Example 1
In preparing a model sample water in which a plurality of chemiluminescence-causing substances including polycarboxylic acids coexist, acrylic acid homopolymer (average molecular weight: 4500, hereinafter abbreviated as “A-1”) and acrylic acid / 2-Acrylamido-2-methylpropanesulfonic acid / 1-butylacrylamide copolymer (average molecular weight: 4500, hereinafter abbreviated as “A-2”) is used as an isothiazolone as a chemiluminescent substance other than polycarboxylic acids. An 8: 2 (weight ratio) mixture of 5-chloro-2-methyl-3-isothiazolone and 2-methyl-3-isothiazolone (hereinafter abbreviated as “A-3”) was used.
[0055]
  Pure water containing polycarboxylic acids and isothiazolonesInIn addition, a series of sample water was prepared by changing the chemical concentrations for both water treatments. These are sample water having a polycarboxylic acid concentration of 7.9 ppm (A-1 is 2.2 ppm, A-2 is 5.7 ppm), an isothiazolone concentration of 0.438 ppm, and a polycarboxylic acid concentration of 15.8 ppm (A -1 is 4.4 ppm, A-2 is 11.4 ppm), the isothiazolone concentration is 0.865 ppm, the sample water is 31.6 ppm (A-1 is 8.8 ppm, and A-2 is 22.2. 8 ppm), and the sample water had an isothiazolone concentration of 1.75 ppm. Further, as reference sample water, in addition to pure water, a series of sample waters containing only polycarboxylic acids having the same polycarboxylic acid concentration as each of the above sample waters, and isothiazolones having the same isothiazolones concentration as each of the above sample waters A series of sample water containing only the same was also prepared using pure water.
[0056]
  100 μL (microliter, the same applies hereinafter) of each sample water was injected from the injector 3 into the carrier liquid, oxidized in the sample oxidation reactor 5, and then introduced into the mixer 6..
[0057]
On the other hand, as the ruthenium complex solution, tris (2,2′-bipyridyl) ruthenium (II) hydrochloride is dissolved in a sulfuric acid aqueous solution having a concentration of 10 mmol / L (the same applies hereinafter) to a concentration of 0.3 mmol / L. The solution prepared in (1) was used. This ruthenium complex solution is fed at a rate of 0.3 ml / min, supplied to the reagent oxidation reactor (electrolytic oxidizer) 4 and continuously electrolyzed at 100 μA to oxidize Ru (II) to Ru (III). did. In addition, pure water was used as a carrier liquid, and the liquid was fed at 0.5 ml / min.
[0058]
The results are summarized in FIGS. FIG. 2 is a graph showing the relationship between chemiluminescence intensity and chemical concentration for both water treatments for a series of sample waters containing both polycarboxylic acids and isothiazolones, and FIG. 3 is a series of samples containing only polycarboxylic acids. FIG. 4 is a graph showing the relationship between chemiluminescence intensity and isothiazolone concentration for a series of sample water containing only isothiazolones. In these figures, “luminescence intensity” is a difference obtained by subtracting the measured value of pure water from the measured value of chemiluminescence intensity of each sample as a background, that is, a correction value.
[0059]
As apparent from FIGS. 2 to 4, it can be seen that by oxidizing the sample water in advance, the chemiluminescence intensity attributed to the isothiazolones can be substantially eliminated, and only the polycarboxylic acids can be selectively detected.
[0060]
Example 2
Polyacrylic acids “A-1” and “A-2” are added to the circulating water of an open circulating cooling water pilot plant having a cooling tower and a heat exchanger, and the initial concentration in the circulating water is 10 ppm (A-1 is 2.8 ppm, A -2 is 7.2 ppm) as an 8: 2 (weight ratio) isothiazolone mixture of 5-chloro-2-methyl-3-isothiazolone and 2-methyl-3-isothiazolone and a stabilizer of isothiazolones. Of bromonitropropanol was added so that the initial concentrations in the circulating water were 0.8 ppm and 1.0 ppm, respectively, and the pilot plant was operated under the following conditions.
Water quality: Toda Industrial Water
Water volume: 2 tons / minute
Circulating water volume: 1 ton
Cooling water inlet water temperature of heat exchanger: 25 ° C
Cooling water outlet water temperature of heat exchanger: 30 ° C
In addition, Toda industrial water corresponding to the amount of evaporated water and the amount of scattered water was replenished, and the concentration factor of circulating water was maintained at about 5 times.
[0061]
Circulating water is periodically sampled, the sample water is treated in the same manner as in Example 1, and the chemiluminescence method and iron-thiocyanate colorimetric method using FIG. 2 as a calibration curve (see Japanese Patent Application No. 10-148615) Were used to measure polyacrylic acid concentrations separately. Table 1 shows the measured concentration values with respect to the elapsed days.
[0062]
[Table 1]

[0063]
As is apparent from the results in Table 1, the polyacrylic acid concentration determined by the chemiluminescence method is in good agreement with the polyacrylic acid concentration determined by the iron-thiocyanate colorimetric method. According to the method of the present invention, the circulating water Even in the presence of polycarboxylic acids and isothiazolones, it was confirmed that the selective quantification of polyacrylic acids in the circulating water was easily performed, and the concentration control of chemicals for water treatment could be easily achieved.
[0064]
【The invention's effect】
According to the present invention, polycarboxylic acids functioning as scale inhibitors, dispersants, anticorrosives, flocculants, etc. (or, if necessary, disinfectants and slimes in the concentration control method for water treatment chemicals in cooling water systems) Since the chemicals to be detected, which are isothiazolones that function as control agents and the like, are active ingredients of water treatment chemicals themselves, the concentration of active ingredients can be directly and easily measured accurately by the chemiluminescence method. Based on the obtained active ingredient concentration value, it becomes possible to perform appropriate concentration management of water treatment chemicals for scale prevention and metal corrosion prevention of cooling water systems, as well as sterilization and slime control. It is also possible to maintain the chemical concentration for treatment at almost the optimum effective concentration, for water treatment such as scale prevention effect, metal corrosion inhibition effect, bactericidal effect, slime prevention effect, etc. While satisfactorily to exhibit the effect of the goods the operation of the cooling water system can be carried out stably economical and rational. In addition, the detection of polycarboxylic acids (or isothiazolones) by the chemiluminescence method according to the present invention has a fast response speed (the time required for the luminescence reaction is short). It is possible to develop a cooling water system water treatment chemical concentration management method incorporating a fully automatic continuous measurement system represented by (FIA: Flow Injection Analysis).
[Brief description of the drawings]
FIG. 1 is a flowchart showing an example of an apparatus for carrying out a chemiluminescence method in the present invention.
FIG. 2 is a graph showing the relationship between chemiluminescence intensity and chemical concentration for both water treatments for a series of sample waters containing both polycarboxylic acids and isothiazolones in Example 1.
FIG. 3 is a graph showing the relationship between chemiluminescence intensity and polycarboxylic acid concentration for a series of sample water containing only polycarboxylic acids in Example 1.
4 is a graph showing the relationship between chemiluminescence intensity and isothiazolone concentration for a series of sample waters containing only isothiazolones in Example 1. FIG.
[Explanation of symbols]
1, 2 pump
3 Injector
4 Reagent oxidation reactor
5 Sample oxidation reactor
6 Mixer
7 Detector
8 Data processor

Claims (3)

A polymerizable monomer having a carboxylic acid group and an unsaturated double bond as a kind of water treatment chemical present in the circulating water after previously oxidizing the circulating water sample in a cooling water system having at least a cooling tower and a heat exchanger The concentration of polycarboxylic acids that are one or more of the group consisting of homopolymers, copolymers, and salts thereof, and complexes of transition metal elements and nitrogen-containing aromatic ligands and / or rare earths Chemiluminescence in which the ammonium nitrate of the element is oxidized to increase the oxidation number of the transition metal element and / or rare earth element, and then the obtained oxidant is brought into contact with the pre-oxidized sample of the circulating water to cause chemiluminescence A method for controlling the concentration of a chemical for water treatment in a cooling water system, comprising a step of measuring by a method. The circulating water further includes isothiazolones as other types of water treatment chemicals, and the step of measuring the total concentration of isothiazolones + polycarboxylic acids by chemiluminescence method without previously oxidizing the sample of the circulating water The method for managing a concentration of a chemical for water treatment in a cooling water system according to claim 1, further comprising: The cooling water system water according to claim 1 or 2 , further comprising a step of adding and replenishing the cooling water system with a necessary amount of the water processing chemical based on the measured concentration value of the water processing chemical. Concentration control method for processing chemicals.

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